1. Field of the Invention
The present invention relates to audio signal processing techniques. More particularly, the present invention relates to methods for decomposing audio signals into primary and ambient components.
2. Description of the Related Art
Primary-ambient decomposition algorithms separate the reverberation (and diffuse, unfocussed sources) from the primary coherent sources in a stereo or multichannel audio signal. This is useful for audio enhancement (such as increasing or decreasing the “liveliness” of a track), upmix (for example, where the ambience information is used to generate synthetic surround signals), and spatial audio coding (where different methods are needed for primary and ambient signal content).
Current methods determine ambience components for each audio channel by applying a real-valued multiplier to the original channel signal, such that the resulting primary and ambient components for each channel are in phase. Unfortunately, these techniques sometimes lead to artifacts in the audio reproduction. These artifacts include the “leakage” of primary components into the ambience, etc. What is desired is an improved primary-ambient decomposition technique.